Control device for lifting pins on molding machines



Dec. 12, 1950 H. J. ROTHSCHILD 2,533,960

CONTROL DEVICE FUR LIFTING PINS 0N MOLDING MACHINES Filed Feb. 10, 1949 2 Sheets-Sheet 1 INVENTOK H. .Rot/zsa/vd/d J UtJWLW ATTORNEBS Dec, 12, 1950 H. J. ROTHSCHILD 2,533,950

CONTROL DEVICE FOR LIFTING PINS 0N MOLDING MACHINES Filed Feb. 10, 1949 2 Sheets-Sheet 2 Fig.6 INVENTOR H pof/vschd/cll M auxmk giw ATTOTLNEJS Patented Dec. 12, 1950 CONTROL DEVICE FOR LIFTING PINS ON MOLDING MACHINES H ns Jakob Rot s hil scha fh e n S tze land, assignor to Georg Fischer Aktiengesellschaft, Schai-fhansen, Switzerland p icat on e ruar .9 :8, S r al 75,706 In Switzerland December 9, 194.8

4 Claims.

The invention relates to a molding machine of the type provided with a vertically displace,- able supporting member for the lifting pins, the locking means of which are controlled by a common control valve. In order toprevent the mold from being damaged during the drawing mQbiOn it is essential to draw the flask with the mold in perfect alignment with the pattern and without any tilting motion.

In prior art the locking of the lifting pins is effected by hand-operated control means. This causes additional manipulations during the molding cycle. In order to attain the simplication of the operation of molding machines of the above described type the present invention has been developed.

The principal object of the invention is to provide control means for locking the mold lifting pins during the whole mold drawing motion.

Another object of the invention is to provide control means for actuating the vibrator only during the very first beginning of the drawing motion.

The drawings show two embodiments of the invention, the figures representing:

Fig. 1 a cross section through a molding machine with the air control valve for the locking device for the lifting pins,

Fig. 2 a first embodiment of the invention; position of the control valve at the beginning of the mold drawing operation,

Fig. 3 the same embodiment as in Fig. 2; position of the control valve when the mold is drawn,

Fig. 4. the same embodiment as in Fig. 2; position of the control valve when the drawin device is in its lowered position,

Fig. 5 a further embodiment of the invention; position of the control valve at the. beginning of the mold drawing operation,

Fig. 6 the same embodiment as in Fig. 5; position of the control valve when the mold is drawn.

Fig. 1 shows the molding machine standard I with the laterally rockable head piece 2 and the vertically adjustable press plate 3. The drawing piston t is rigidly secured to the machine standard i. On the drawing piston is vertically slideable the drawing cylinder 5, with which are connected the supporting frame 6, the adjustable members i and the lifting pins 8. On the molding machine table 9 rests the molding plate In with the pattern 11; the flask l2 with a mold is shown in drawn position.

Supply conduit 14 leads into the pilot valve 16. Conduit 38 is branched-off from the supply conduit I4 and leads int the trol val e b dy L 2 Conduit It connects the pilot valve IS with the control valve body i3 and conduit 39 connects the conduit 15 with the upper end of the lifting cylinder 5 The exhaust conduit It leads from the pilot valve it into the atmosphere.

The abutment is fixed to the molding machine standard 1 serves, as end stop for the stroke length of the drawing cylinder 5 and the arm 20 on top of the drawing cylinder 5 serves for actuating the stem 24 of the neutral valve is. Conduit 2| connects the control valve body it with the lifting pin locks 53 and the conduit 22 the control valve body 18 with the vibrator '23.

Figs. 2, 3 and 4 show the details of a first embodiment of this invention as follows:

Slideably mounted in the valve body [8 is the valve stem 24 with the valve piston 35 and the valve cone 3?. The screw 25 serves for closing the control valve body it. The parts 55, 2|, 22, 38 and 39 are numbered according to the various conduits as indicated in Fig. 1. The same is the case with the other parts shown in Figs. 2, 3 and 4.

Figs. 5 and (i show the details of a second embodiment of this invention as follows:

In a part of the molding machine standard I the drawing cylinder 5 slides vertically on top of which is attached the rack til. Rigidly connected with the machine standard I is the control valve body 3| with the valve plug 32 at the one end of which is connected the lever as with the weight 34. A part of the hub of the lever 33 is provided with teeth 35 which engage with the teeth of the rack 31]. The ports l5, 2|, 2?, 38 and 39 are numbered to correspond to the conduits as indicated in 1.

The operation of the control valve according to Figs. 1, 2, 3 and 4 is carried into effect as follows:

On a molding machine of the type shown in Fig. 1 a mold box or flask E? has to be drawn or lifted from the pattern ii on the molding plate 10 by means of the lifting pins 3. At the beginning of the drawing operation the drawing cylinder 5, the supporting frame t, the adjustable member 1 and the liftin pin locks l3 with the lifting pin 8 rest in their lowermost position. In this position the arm 2% on top of the drawing cylinder 5 stays at the point indicated by interrupted lines in Fig. 1. The condition existing in the control valve body 18 is shown in Fig. 2.

The supply conduits L5 and 38 remain under air pressure during the whole molding cycle. Compressed air enters continuously through port 33 of the control valve body it and builds up a pressurebelow valve piston 36 on valve stem 24.

For initiating the drawing operation of the molding machine the lever of the pilot valve I6 is turned into such a position that air from the pilot valve it enters into the conduits l and 39. As indicated in Fig.2 the air is entering at 55 and it flows through the Valve body It to the conduit 2! which leads to the lifting pin locks 13 and to conduit 22 which leads to the vibrator 23. This means that the vibrator 23 begins to work and that the lifting pins 8 are locked by means of the lifting pin locks l3. At the same time air is entering through conduit 39 into the drawing cylinder 5 which commences to ascend together with the parts 6, l, 8 and [3.

The air pressure in conduit 38 presses the valve piston 35 in upward direction against the arm which ascends and descends together with the drawing cylinder 5. As soon as the ascending movement has been initiated the arm 26 and the valve cone 3? are lifted by the pressure below the valve piston 36 and the valve cone 3 closes the air supply from the conduit E5 to the conduit 22, while the piston 36 closes the air suppl from the conduit 55 to the conduit 2!. Conduit 22 is now and remains without air pressure; i, e. the vibrator 23 ceases to work. Conduit 2| is now receiving air from the supply conduit 38 and the lifting pins 8 remain locked. This condition corresponds to Fig. 3 and the lifting cylinder 5 proceeds in its ascending motion until it is stopped 5 by the abutment 9. The locking pins and their operation are set forth in greater detail in the description of Figure 3 of Patent No. 2,376,203, belonging to the same assignee.

When the drawing operation is completed the mold 82 may be removed from the still locked lifting pins 8 and now the latter have to be brought back or lowered to their initial position. To efiect this descending motion the pilot valve I6 is turned to a position wherein the conduits i5 and 39 are connected with the exhaust conduit ii. The air from the drawing cylinder 5 exhausted at conduit I1 and the latter, together with the parts 6, 'l, 3 and i3 descend into their lowermost position. In this position the arm 26 presses down the valve stem 24 against the action of the air pressure from the conduit 3% below the valve piston 33; the air from the lifting pin locks i3 is exhausted through the conduits 2i, l5 and I1.

The operation of the second embodiment of the control valve according to Figs. 1, 5 and 6 is as follows:

The general arrangement and the enumeration of the various conduits remain the same as shown in Fig. 1. In the lowermost position of the drawing cylinder 5, the teeth of the rack 30 are in engagement with the teeth in the hub of the lever 33, which is connected with the valve plug 32. The control Valve is in the position shown in Fig. 5.

To initiate the drawing operation of the molding machine the lever of the pilot valve is is turned to such a position that air enters from the supply conduit M into the conduits l5 and 39. Fig. 5 shows that in the control valve body 3i the air from conduit l5 enters into the conduits 2!, leading to the lifting pin looks it, and conduit 22 leading to the vibrator 23.

At the same time air enters through the conduit 39 into the drawing cylinder 5 and the latter begins to ascend. By means of the rack 33 and the engaging teeth 35 in the hub of the lever 33 the valve plug 32 begins to revolve and closes the air inlet port l5 and the air outlet port 22;

i. e. the vibrator 23 stops working. The valve plug 32 is now in the position shown in Fig. 6 and remains there because of the weight 34 which keeps the valve plug 32 in this position. Conduit 2!, which leads to the lifting pin'locks I 3, now receives air from the conduit 38 which is constantly kept under pressure. The ascending motion keeps out until the drawing cylinder 5 touches the abutment l9.

When the drawing motion is completed the mold I2 is removed from the lifting pins 8 and the descending motion of the drawing cylinder 5, together with the attached parts 6, 1, El and [3, may be initiated. To effect this motion the pilot valve 16 is turned to such a position that the conduits l5 and 39 are connected with the exhaust conduit ll. The drawing cylinder 5 begins to descend and when it is nearing its lowermost position the teeth of the rack 3!] become engaged with the teeth 35 in the hub of the lever 33. Against the action of the weight 34 the valve plug 32 is now turned to the position indicated in Fig. 5 with the exception that now the conduit I 5 is without pressure.

The utilization of a control valve of the above described type offers the advantages that the lifting pins automatically remain locked during the whole drawing operation. This is effected by means of the centrally controlled lifting pin looks. The vibrator 23 remains in operation only during the very first moments of the drawing motion which is sufiicient to loosen or free the sand of the mold from the pattern.

I claim:

1. A molding machine, comprising, in combination, a vertically displaceabledrawing cylinder, mold-lifting pins, pneumatic locking means connected with said pins for locking the same, means operatively connecting said locking means with said cylinder to move said pins along with said cylinder, a pilot valve, a control valve having a casing and a valve body; supply conduits connecting a compressed air source to said pilot valve and said control valve casing, supply conduits connecting said pilot valve with said drawing cylinder and said control valve casing, whereby said drawing cylinder is actuated by compressed air from the first of said last-mentioned supply conduits, a conduit connecting said control valve casing with said pneumatic locking means, said control valve body being movable in said'casing to either of two end positions, said valve body in one of said end positions connecting said pilot valve withsaid locking means and interrupting this connection and connecting said compressed air source withsaid locking means, during its movement from said one end position to the other end position, and means carried by said drawing cylinder and engaging said valve body in the lowermost position of said cylinder to maintain the valve body in said one end position while said drawing cylinder is in its lowermost position.

2.'A machine in accordance with claim 1,

wherein said valve body comprises a valve stem and wherein the last-mentioned means consist of an arm engaging said valve stem in the 1owermost position of said drawing cylinder.

3. A machine in accordance with claim 1, wherein said valve body comprises a lever and teeth upon said lever, and wherein the lastmentioned means consist of a rack engaging said teeth inthe lowermost position of said drawing cylinder.

l. A molding machine, comprisingqin combination, a vertically displaceable drawing cylinder,

mold lifting pins, pneumatic locking means connected with said pins for locking the same, means operatively connecting said locking means with pressed air from the first of said last-mentioned supply conduits, a conduit connecting said control valve casing with said pneumatic locking means,

a conduit connecting said control valve casing with said vibrator, said control valve body being movable in said casing to either of two end positions, said valve body in one of said end positions connecting said pilot valve with said locking means and said vibrator and interrupting these connections during its movement to the other end position and connecting said compressed air source with said locking means, and means carried by said drawing cylinder and engaging said valve body in the lowermost position of said cylinder to maintain the valve body in said one end position while said drawing cylinder is in its lowermost position.

HANS JAKOB ROTHSCHILD.

REFERENCES CITED The following referencesare of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,221,452 Johnson Apr. 3, 1917 1,627,956 Cole May 10,. 1927 1,957,246 Byerlein May 1, 1934 2,376,203 Stemmler -1 May 15, 1945 2,438,218 Johnston Mar. 23,. 1948 

